Cocoa beans are the principal raw material for chocolate production. These beans are derived from the fruit pods of the tree Theobroma cacao, which is cultivated in plantations in the equatorial zone, e.g., in Ivory Coast, Ghana, and Indonesia. The cocoa beans are embedded in a mucilaginous pulp inside the pods. Raw cocoa beans have an astringent, unpleasant taste and flavour, and have to be microbially fermented, dried, and roasted to obtain the desired characteristic cocoa flavour and taste. Chocolate flavour is influenced by the origin of the cocoa beans, the cocoa cultivars, the on-the-farm fermentation and drying process, and the roasting and further processing performed by the chocolate manufacturer.
After removal of the beans from the pods, the first step in cocoa processing for e.g. for the cocoa variety forastero is a spontaneous 6 to 10-day fermentation of beans and pulp in heaps, boxes, baskets, or trays. However, the spontaneous cocoa fermentation process is very inhomogeneous and suffers from great variations in both microbial counts and species composition, hence metabolites and start of bean fermentation. The variations seem to depend on many factors including country, farm, pod ripeness, post-harvest pod age and storage, pod diseases, type of cocoa, variations in pulp/bean ratio, the fermentation method, size of the batch, season and weather conditions, the turning frequency or no turning, the fermentation time, etc. which makes reproducibility of fermentation particularly difficult.
Drying of fermented beans may for instance comprise artificial drying in a current of hot-air or by spreading out the cocoa beans in the sun to dry. The roasting step involves Maillard reactions between reducing sugars and hydrolysis products of proteins, especially peptides and free amino acids. Unfortunately, the conditions for drying and roasting are not always adequately controlled. In addition, dried cocoa beans can also be damaged during their transport to the countries specialized in the downstream processing of the beans. Industry must therefore address a wide variability in the composition of a batch of cocoa beans.
Fermentation is known in the art to be an important factor in flavour development in cocoa beans. Attempts have therefore been made in the prior art to control fermentation parameters. Also, attempts have been made in the prior art to prepare cocoa beans having a desired composition, flavour and/or organoleptic properties.
For instance, WO 2007/031186 discloses a method to regulate the fermentation of plant material consisting of cocoa beans and/or pulp by adding to said plant material specific bacterial cultures containing at least one lactic acid bacterium and/or at least one acetic acid bacterium at different times during the fermentation process.
For instance, US 2002/0034579 discloses a method to obtain flavour-reduced or low-flavour cocoa from unfermented cocoa beans. In this method, the harvested cocoa beans are liberated from the pulp surrounding them and are optionally dried. The disclosed method further comprises the incubation of the (un)dried unfermented beans in water, the subsequent treatment in an acid aqueous medium after which the treated beans are subjected to an oxidation treatment. However, this method suppresses the formation of flavour and hence low-flavour cocoa is obtained.
WO 97/33484 discloses a process for reducing the levels of acidity in fermented beans prior to drying of the beans. In order to improve and enhance cocoa flavour of such beans, fermented beans were at least partially deshelled prior to drying, e.g. by means of air drying or sun-drying. During drying, excess acids diffuse from the beans to the shells where they are lost either by evaporation or by microbial decomposition. However, in this method, the drying step must be sufficiently long to result in a reduction of the level of acidity in the beans. The temperature of the process cannot be risen too high in order not to affect enzyme activity, responsible for flavour improvements, in the beans.
However, fermentation parameters remain difficult to control in prior art methods and industry must therefore address a wide variability in the composition of a batch of processed cocoa beans. Also there remains a need in the art for further controlling fermentation processes of cocoa beans in order to obtain highly flavoured cocoa beans of good quality.